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Gerstley Borate Glaze Calculation examples

Examples of how we use glaze calculations (in an Insight-Live.com account) to replace Gerstley Borate with other materials, especially frits, in various glaze recipes. In doing so we take the opportunity to improve the recipe in other ways (e.g. reduce thermal expansion, improve slurry properties, reduce bubbling and crawling).

Related Information

Ferro Frit 3134 is NOT A SUBSTITUTE for Gerstley Borate

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This frit, or any of similar chemistry (e.g. Fusion F-12) IS NOT A 1:1 SUBSTITUTE for Gerstley Borate, their chemistries are too different. That being said, the frit sources lots of B₂O₃, which makes it a candidate to weave into recipes as the source of boron. To show the difference, I have put 100 parts of each in side-by-side recipes in my Insight-live.com account, set the calculation type to non-unity formula and increased the frit until the B₂O₃ in the two match. Notice it takes 118g of the frit to source the same amount of B₂O₃ as 100 GB. Notice also that the frit sources almost triple the amount of Na₂O per weight unit (that is a big deal because it means the recipe containing the Gerstley Borate to be substituted needs an Na₂O-sourcing material that can be reduced to compensate). And the frit sources 3.5 times the SiO₂ (other SiO₂-sourcing materials in the recipe will need to be cut to compensate). And the Gerstley Borate has significant MgO while the frit has none (so an MgO-sourcing material like talc will be needed). Minor tweaks will also be needed to reduce other sources of CaO (since the frit has quite a bit more). The recipe will also need enough flexibility to do the final matching of Al₂O₃ and SiO₂. The GBMF test confirms the difference at 1700F; these 10-gram balls melted down onto the tiles very differently.

Links

URLs	https://insight-live.com/insight/share.php?z=HzyNzj9ELs Replacing the Gerstley Borate in recipes containing 50% or more of it Many recipes were built on bases employing exceptionally high percentages of Gerstley Borate. At medium temperatures these melt fluid transparents hosted additions of colorants, variegators and opacifiers. At low fire they were used as transparents over underglaze decoration.
URLs	https://insight-live.com/insight/share.php?z=6TesQXNkkA Removing the Gerstley Borate from Randy's Red glaze
URLs	https://insight-live.com/insight/share.php?z=oLZXQTy9TR Floating Blue - Substituting Gerstley Borate The original floating blue recipe shown side-by-side with variations made using frits instead of Gerstley Borate (and titanium and iron instead of rutile).
URLs	https://insight-live.com/insight/share.php?z=td5N6ka2kx Learn about common Gerstley Borate recipes This home page enables viewing the common glossy glaze types, both recipes and calculated chemistry. Notes to help understand them are included.
Materials	Gerstley Borate Gerstley Borate was a natural source of boron for ceramic glazes. It was plastic and melted clear at 1750F. Now we need to replace it. How?
Video	How I Developed the G2926B Cone 6 Transparent Base Glaze How I found a pottery glaze recipe on Facebook, substituted a frit for the Gerstley Borate (using glaze chemistry), compared using a melt flow tester, added as much extra SiO2 as it would tolerate, and got a durable and easy-to-use cone 6 clear.
Media	Getting Frustrated With a 55% Gerstley Borate Glaze I show you why people love/hate this material and how I substituted it for Ulexite in this crazy recipe to make a far easier-to-use slurry that fires identical.
Media	Use Insight-live to substitute materials in a recipe We will substitute wollastonite for whiting and a frit for Gerstley borate in the G2571A cone 10 matte while maintaining the chemistry of the original recipe.
Typecodes	Common Gerstley Borate glaze recipes Many of the glazes in use are built on common base recipes. And there are some universal recipes that almost everyone uses, we may have already converted those for use with frits.
Typecodes	Gerstley Borate Substitutes Many development efforts to create Gerstley Borate substitutes took place during the early 2000s (the initial period when the demise of Gerstley Borate appeared imminent). A number of companies, including Laguna Clays itself, produced and sold these for many years. When Laguna secured another stockpile at the mine and began producing the original material again, interest in substitutes gradually waned. However, the sudden dramatic price increase in 2023 appears to have initiated the process again. Gillespie Borate appears to be the only viable and visible substitute now. Thus, the substitutes listed here are mostly no longer made. Other high-boron materials shown are also no longer available. We continue to recommend sourcing B2O3 from frits instead. Please contact us if you have a specific recipe and we can work with you in your Insight-live account to develop a new recipe that both eliminates the GB and improves overall working and firing properties.

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